Visual sense examining chart

ABSTRACT

An eye test chart includes a visual target for multiple test purposes composed of patterns of combinations of at lest two or more kinds of colors and predetermined shapes that are arranged at predetermined positions on an image area corresponding to visual field regions to be examined. Color vision defects and their abnormal regions can be identified as a result of a subject&#39;s visual identification of the visual targets arranged at the predetermined positions.

TECHNICAL FIELD

[0001] The present invention relates to an eye test chart used forexamining visual field defects, metamorphopsia, or color defectivevision caused by eye diseases, such as those of the retina and opticnerve, or intracranial diseases etc., and particularly to an eye testchart capable of making easy the detection of early symptoms or progressobservation.

BACKGROUND ART

[0002] Tests on vision are important not only in ophthalmology todiagnose eye diseases such as those of the retina and optic nerve, butalso in neurology or brain surgery to diagnose intracranial diseases,and various kinds of test apparatuses or charts, such as Goldmannperimeter and Humphrey perimeter, have been conventionally used.

[0003] Test methods using conventional apparatuses or charts, however,limit test items to one per apparatus or chart. When multiple test itemssuch as metamorphopsia and color defective vision need testing, multipleapparatuses or charts are needed for the test, which is time-consumingand troublesome. In addition to being troublesome, it requires thecontinuous attention of persons being tested, or subjects, causing theirfatigue. Furthermore, the use of the conventional test apparatuses orcharts makes it difficult for the subjects to become aware of theirabnormal regions, and hence to figure out their symptoms.

[0004] Further, since conventional test apparatuses are very big,floor-mounted type apparatuses, they are difficult to carry around. Inthe case of the use of a test apparatus using light as a visual target,a test-specific space and environment that provide a “semidark” room hasbeen required. In such a case, any subject has to come over to theinstallation site of the test apparatus and maintain a predeterminedposition to undergo a test, and this makes it very difficult forbedridden patients to undergo the test.

[0005] Further, a patient who is not aware of early symptoms of eachdisease causing visual impairment does not know that he or she has thedisease until after the disease reaches such an advanced stage thatsubjective symptoms appear, he or she visits a medical institution andthe disease is diagnosed by ophthalmology. Thus there has been a problemthat early detection of the disease is difficult.

[0006] Therefore, the development of an eye test chart capable ofcarrying out eye tests of multiple items simultaneously and easily hasbeen strongly desired.

DISCLOSURE OF THE INVENTION

[0007] It is an object of the present invention to provide an innovativeeye test chart that meets such a desire.

[0008] According the present invention, there is provided an eye testchart on which multiple visual targets composed of patterns ofcombinations of at least two or more kinds of colors are arranged atpredetermined positions corresponding to visual field regions to beexamined. Using this chart, it is checked whether the combinations ofcolors and the shapes different in the position of the targets can beidentified or not, thus carrying out detailed eye tests for each regionto be examined.

[0009] In one preferred embodiment, the visual targets include circularor square targets of two or more kinds of colors different in hue andcomplementary to each other. Based on such a figuration, it is checkedwhether the shapes or profile straight or curved lines can be visuallycorrectly identified, thereby enabling the detection of visualimpairment. Since the colors are different in hue, it is easy tovisually identify the visual targets, and if they are complementarycolors, it will be further easier to visually identify them. Then, it ischecked whether the colored conditions can be visually correctlyidentified, thereby also enabling the examination of the presence orabsence of color defective vision. The visual targets also includecircular or square targets divided into four parts in a checkeredpattern of a combination of two kinds of colors different from thebackground color, or circular or square targets each composed of avertical striped pattern of two kinds of colors. It is checked whetherthey can be visually correctly identified to enable the examination ofthe presence or absence of visual field defects and metamorphopsia. Thedirection of the striped pattern may be changed to determine theastigmatic direction. In addition, the striped pattern is formed suchthat one color shifts to the other in a sinusoidal fashion. This makesit easy to detect a pathological blind spot in the macular area, thatis, even in a part where sensitivity is reduced. On the eye test chart,a fixed target having a color or colors different from those of saidcircular or square targets, or a profile line (grid, etc.) bolder thanthose of the other targets is also arranged at the center. Then, gridtargets composed of a grid of squares in which the circular or squaretargets are displayed are arranged in parallel around the fixed targetin both the longitudinal and transverse directions. Using this chart, itis checked whether there are parts in the chart that look missing ordisappear from the eye, whether the grid squares of the grid targetslook skewed, and whether the striped pattern or checkered pattern can bevisually correctly identified. It allows the examination of the presenceor absence of central and paracentral visual field defects andmetamorphopsia. Further, enlarged circular or square targets formed byjust enlarging the pattern of the circular or square targets arrangedinside the grid targets are arranged vertically and horizontally inparallel to enable the detection of a visual field detect even in aperson with low visual acuity.

[0010] In another preferred embodiment, band-shaped targets formed inthe shape of a band with a checkered pattern of multiple squares, eachcomposed of the striped pattern or checkered pattern with the fourdivided parts, are arranged around the central portion of the eye testchart vertically and horizontally in parallel. It allows the detectionof a visual field defect in the Bjerrum area. The difference in color,rather than the striped pattern, is used to identify the four-dividedsquares in the checkered pattern so that the band-shaped targets can beidentified even by the eye with low sensitivity. On the eye test chart,a set of blind-point targets for determining Mariotte's blind spot,composed of a combination of one or more black figures, is also arrangedat a predetermined bilateral position, so that the proper positionalrelation between the chart and the eye can be maintained, therebycarrying out the eye tests easily and accurately. Further, multipleblind-spot peripheral targets colored with a color different from thebackground color and easy to visually identify are arranged around theblind-spot targets in a bilaterally symmetrical pattern. The use of theblind-spot peripheral targets makes it possible to check whether theextent of Mariotte's blind spot is widened. In addition, large-sizedsquare targets, each of which is a black square larger than any othersingle circular or square target, and which contains two figures coloredwith the background color or a color of high lightness and spaced at apredetermined interval, are arranged on four corners of the eye testchart. Then, at least two or more parallel square targets, each of whichis composed of a hollow figure shaped like a Chinese character “

” with the figure parts colored with a color different from thebackground color and easy to visually identify and the hollow partscolored with the background color, are arranged at both top and bottomsides, or at both right and left sides, in parallel in the transverse orlongitudinal direction. Further, at least two or more parallel circulartargets, each of which is composed of a hollow figure shaped like anumber “0” with the figure parts colored with a color different from thebackground color and easy to visually identify and the hollow partscolored with the background color, are arranged at both top and bottomsides, or at both right and left sides, in parallel in the transverse orlongitudinal direction. The use of these targets different in shape andcolor enables the examination of the eye's resolution in each diseaseregion and each stage of the disease. These targets can also be used toa detect visual field detect or hemianopia, and further a nasal step inglaucoma.

[0011] All the above-mentioned targets are arranged in a bilaterallysymmetrical pattern to enable an accurate comparison of visualimpairment in both right and left eyes.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a front view showing a preferred eye test chartaccording to the present invention.

[0013]FIG. 2 is a partially enlarged front view showing the eye testchart of FIG. 1.

[0014]FIG. 3 is a front view showing another preferred eye test chartaccording to the present invention.

[0015]FIG. 4 is a front view showing still another preferred eye testchart according to the present invention.

[0016]FIG. 5 is a front view showing yet another preferred eye testchart according to the present invention.

[0017]FIG. 6 is a front view showing yet another preferred eye testchart according to the present invention.

[0018]FIG. 7 is a front view showing the other preferred eye test chartaccording to the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

[0019] The present invention will now be described in more detailaccording to the accompanying drawings.

[0020]FIGS. 1 and 2 show the first feature of the present invention. Aneye test chart 1 that assumes the form of a test plate 11 is printed inan image area 10 of about A3-size board made of synthetic resin, showinga test chart 1A on the background of bright color such as yellow.

[0021] The test chart 1A is made up of grid targets 3 composed of a grid32 of squares arranged in a black grid pattern 31 in both thelongitudinal and transverse directions, and circular targets 4 arrangedinside the squares of the grid and colored with a vertically stripedpattern of various color tones. Then a central square 310 is surroundedby a box frame bolder than any other squares on the grid pattern, and acircular target displayed inside the central square is set as a fixedtarget 40 used to fixate subjects' gaze at one specific location. Thefixed target 40 may be colored with a striking hue, such as red,different from those of the other circular targets 4.

[0022] The circular target 4 shown in an enlarged view of FIG. 2, forexample, has a pattern of vertical stripes colored with different hues,shades of gray, etc., or a pattern of vertical stripes of two colorsthat may be yellow, the same color as the background, and a color (forexample, blue) different in hue from the background color. Further, eachcircular target 4 may be varied in color or tin, and the pattern ofvertical stripes may be made with such a two-color gradation that onecolor shifts to the other in a sinusoidal fashion.

[0023] Using this test chart, an examiner checks if a subject canvisually identify the central circular target as the fixed target 40when viewing it with one eye from the front. It allows the examiner toexamine the presence or absence of a central visual field defect causedby a disease, such as a disease in the macular area like maculardegeneration or a disease of the optic nerve like optic atrophy. Theexaminer can also check if the subject can visually identify all partsof the test chart 1A without any break of sense to examine the presenceor absence of a visual field defect or hemianopia and, if any, the typeof defect.

[0024] Simultaneously, the examiner checks if the grid pattern of thegrid targets 3 look skewed to the subject, thereby enabling theexamination of the presence or absence of metamorphopsia caused by adisease in the macular area. Then, the examiner checks if the subjectcan visually identify differences in color, presence or absence ofvertical striped pattern, etc. in those differently colored circulartargets 4, thereby enabling the examination of the presence or absenceof a color vision defect and, if any, the type of defect.

[0025] The above test chart 1A is bilaterally symmetrical about thecentral circular target as the fixed target 40, so that not only canboth the right and left eyes be examined in the same manner, but alsothe presence or absence of hemianopia can be examined. It is alsovertically symmetrical, so that the vertical fields of vision can beexamined under the same conditions.

[0026] The following describes the procedure of eye tests using the eyetest chart 1.

[0027] First of all, a subject looks through all parts of the test chart1 with both eyes open and reads an instruction book or leaflet on thetest chart to make sure the placement of respective targets, conditions,etc. Then the subject covers one eye with a special-purpose eye patch orhand from an appropriate distance from the image area 10, for example,at a position about 40 cm away from the test chart 1, and fixes his orher eye to be tested on the central fixed target 40 from the front inthe vertical direction. Then the subject checks if the central square310 and the circular target inside the central square are correctlyvisible.

[0028] Next, the subject checks if part or all of the grid targets 3look skewed, dim, or missing, and if part or all of the circular targets4 look missing or disappear from his or her eye, etc. The subject alsochecks if he or she can visually identify the correct colors and patternof vertical stripes in the circular targets 4 and if there are nomissing parts. These tests allow the examination of the presence orabsence of symptoms of central and paracentral visual field defects,hemianopia, metamorphopsia, and color defective vision, such ascongenital red-green color deficiency or acquired blue-yellow colordeficiencies caused by optic nerve disorders.

[0029] During the tests, the subject should be careful not to alwayslook away from the central fixed target 40 so that the examination willbe carried out from the correct position. If an examiner witnesses thetests, he or she should keep on alerting the subject to the position ofthe subject's eye.

[0030]FIG. 3 shows the second feature of the present invention,illustrating an eye test chart 2. On the eye test chart 2, the gridpattern 31 of the grid targets 3, which is made up of the grid ofsquares on the eye test chart 1 in FIG. 1, is formed in the shape of ahuman-like robot with targets of various colors and shapes arrangedaround the grid pattern.

[0031] The shape, colors, pattern, etc. of the circular targets 4 inrespective squares of the grid 32 are set in the same manner as those inFIG. 1, but a circular target 4 inside a central square 32 a is coloredwith a striking hue, such as red, so that it will be set as a fixedtarget 41. The other circular targets 4 have a pattern of verticalstripes colored with different hues, such as yellow, the same color asthe background, and another color, like blue, different in hue from thebackground. In this case, the tests on the presence or absence ofcentral and peripheral visual defects, hemianopia, etc. and the tests onthe presence or absence of symptoms of metamorphopsia and colordefective vision can be carried out in the same manner as those usingthe eye test chart 1 in FIG. 1.

[0032] Further, band-shaped targets 5 composed of blocks of multiplestriped patterns arranged in the shape of a band with two rows ofcheckered patterns are displayed around the grid targets 3. Theseband-shaped targets are used to detect visual impairment in the Bjerrumarea. The striped pattern in each square forming part of the band-shapedtargets 5 may be displayed with two different color tones that are equalin hue but contrastive in terms of the lightness of color, for example,such that the inner row is made with a vertically striped pattern of apale color and the outer row is made with a horizontally striped patternof a deep color. Both striped patterns may be made with a gradation inthe same manner as the vertically striped pattern of the circulartargets 4.

[0033] Furthermore, parallel targets 7 and large-sized square targets 8,both being larger than any other targets in the central portion, aredisplayed near the periphery of the image area 10. The parallel targets7 are made up of parallel circular targets 71, each of which containsmultiple 0-shaped, hollow oval figures and which are arranged at bothright and left sides of the image area relative to the fixed target 41as the center, and parallel square targets 72, each of which containsmultiple figures shaped like a Chinese character “

” and which are arranged at both top and bottom sides. The multipleparallel targets of each type are displayed in parallel with each other.These targets are colored, for example, with a color that is easy tovisually identify, like red or blue, against the background of yellow,but they may be displayed with any other different hue depending on theplacement and shape of the parallel targets 7. On the other hand, thelarge-sized square targets 8, each of which contains FIGS. 82 and 83 ofa falling star cut out from a large-sized black square 81 (thebackground color such as yellow shows through the cutouts) are displayedon the four corners of the image area 10.

[0034] The parallel targets 7 and the large-sized square targets 8 areused to examine vision in the peripheral visual field, where theretina's sensitivity is low, and mainly to examine the eye's resolutionas to whether the two figures spaced at a certain distance lookconnected together or whether the hollow parts look filled up. Thesetargets may be varied in size, shape, and color, and arranged at severalpositions around the periphery of the chart, so that a detailedexamination can be made for each subject, such as the detection of avisual field defect or hemianopia, and further the detection of a nasalstep in glaucoma.

[0035] Blind-spot targets formed by a combination of multiple blacksquares are displayed at appropriate positions bilaterally symmetricalabout the fixed target 41. The blind-spot targets 6 are arranged asMariotte's blind spot that disappears from the subject's eye gazing atthe fixed target 41 from the front when the distance between the imagearea 10 and the eye becomes 40 cm, for example. The position of the eyeat the time the blind-spot targets disappeared is decided as theposition at which the eye tests are carried out. The blind-spot targets6 are colored with a color different from those of the other targets toenable accurate determination of whether the subject can visuallyidentify them or not, and in general, the color is black so that anysubject can use them regardless of the presence or absence of colordefective vision. It should be noted that the shape is not limited tothe checkered pattern as shown in FIG. 3.

[0036] Then, multiple blind-spot peripheral targets 62, each of whichis, for example, formed of two squares, are displayed around theblind-spot targets 6, up and down, and right and left, at an appropriateinterval from the blind-spot targets 6. These targets are used toexamine whether the extent of Mariotte's blind spot is widened due to adisease of the optic nerve or the optic disc such as choked disc.

[0037] The above-mentioned targets are arranged at positions bilaterallysymmetrical about the fixed target 41, so that not only can both theright and left eyes be examined in the same manner, but also thepresence or absence of hemianopia can be examined. They are alsosubstantially vertically symmetrical, so that the vertical fields ofvision can be examined under the same conditions in the same manner asthose using the eye test chart 1 of FIG. 1.

[0038] It is preferable that all the above-mentioned targets bedisplayed with the color complementary to that of the background or deepcolors of different hues to make it easy to distinguish from the yellowbackground of the image area 10. It is also preferable that they bedisplayed with different hues according to the position and shape ofeach target to make it easy to judge whether the subject can visuallyidentify the target.

[0039] The following describes the procedure of eye tests using the eyetest chart 2.

[0040] First of all, a subject looks through all parts of the test chart2 to make sure the shape and placement of each target. Then, forpre-examination, the subject covers one eye with a special-purpose eyepatch or hand from an appropriate distance from the image area 10, forexample, at a position about 40 cm away from the test chart 2, and fixeshis or her eye to be tested on the fixed target 41 from the front in thevertical direction to check if the large-sized square targets 8displayed on the four corners are visible in the same way withoutturning his or her eye.

[0041] Then the subject checks if the vertically striped pattern of thefixed target 41 disappears from his or her eye, if part or all of thevertical stripes 31 of the grid targets 3 look skewed, dim, or missing,if the head and limb parts of the grid targets 3 arranged in the shapeof a robot are visible without any missing parts, if there are missingparts in the circular targets 4 and their vertical stripes, etc. Thesetests are also carried out for examining the presence or absence ofcentral visual field defects or metamorphopsia mainly caused by adisease in the macular area or the like, and the presence or absence ofcolor defective vision caused by a disease of the optic nerve.

[0042] Next, the subject detects a position at which the blind-spottargets 6 disappear from his or her eye gazing at the fixed target 41.The blind-spot targets 6 are so arranged that they will disappear at adistance of 40 cm from the image area 10. Although subsequent eye testsare carried out at the position, when the blind spot targets 6 do notdisappear even if the subject changes the distance between the imagearea 10 and the eye around 40 cm little by little, the distance of 40 cmis maintained throughout the remaining eye tests by measuring it with aruler.

[0043] Then, when the blind-spot targets 6 has disappeared, the subjectchecks if all parts of the blind-spot peripheral targets 62 arrangedaround the blind-spot targets 6 are visible from the position to examinewhether Mariotte's blind spot is widened or not.

[0044] Then, the subject checks if the checkered pattern of theband-shaped targets 5 arranged around the grid targets 3 are correctlyvisible as the checkered pattern, if the color of the squares in thesame row looks different, and if the striped pattern looks correctly.

[0045] After that, tests on the peripheral visual field are carried outusing each target arranged around the periphery of the image area 10.First of all, the subject checks if the star 82 and the band 83 in thelarge-sized square targets 8 displayed on the four corners with theshape of the falling star cut out from the black squares are seen asseparate from each other, if the large-sized targets 8 on the fourcorners look the same, and if the black squares 81 look skewed, and thenchecks if each set of the parallel targets 7, composed of the parallelsquare targets 72 shaped like a Chinese character “

” and arranged in parallel at both top and bottom sides, and the0-shaped parallel circular targets 71 arranged in parallel at both rightand left sides, looks like the same figures are in line with each other,and if no parts look missing or skewed.

[0046] During the tests, the subject should be careful not to alwayslook away from the fixed target 41 so that the examination will becarried out from the correct position. If an examiner witnesses thetests, he or she should keep on alerting the subject to the position ofthe subject's eye.

[0047]FIG. 4 shows the third feature of the present invention,illustrating an eye test chart 2B. The eye test chart 2B is such thatgrid targets 3 b are used instead of the circular targets 4 arrangedinside the grid targets 3 on the eye test chart of FIG. 3. The gridtargets 3 b contains square targets 4 b, each of which is divided intofour squares in a checkered pattern of a combination of two kinds ofcolors different in hue, for example. Further, instead of theband-shaped targets 5 arranged around the grid targets 3 in the shape ofthe band with the checkered patterns of the multiple stripes,large-sized square targets 4 c enlarged from the square targets 4 b areused as elements of band-shaped targets 5 b arranged in the shape of aband of checkered patterns around the grid targets 3 b. This chartparticularly allows for the detection of a glaucomatous visual fielddefect and a scotoma created by macular degeneration.

[0048] It should be noted that a fixed target 42 on the eye test chart2B is a circular target colored with a striking color like red andarranged in one of the grid targets 3 b located at the center of therobot.

[0049] Each of the square targets 4 b is made up of four divided squaresin a checkered pattern (patch pattern) of two kinds of colors differentin hue from yellow as the background color. The two kinds of colors aredifferent in hue, for example, to enable a normal eye to determine thecheckered pattern. Even when the two kinds of colors have the samelightness, they can be easily distinguished if they are complementarycolors, like orange and green. The square targets 4 b enable evensubjects of low visual sensitivity to identify the difference of colorscompared to the circular targets 4 with the striped pattern forming eachcircle.

[0050] The band-shaped targets 5 b composed of the enlarged squaretargets 4 c and arranged around the grid targets 3 b are made up ofelements formed by enlarging the square targets 4 b, and they are easierto identify than the striped patterns of the band-shaped targets 5 ofFIG. 3. The other targets on the eye test chart 2B are the same as thoseon the eye test chart 2 of FIG. 3, and the procedure and method are alsothe same.

[0051] The detection percentage of glaucomatous visual field defects is50 percent or more at Stage I, 80 to 90 percent at Stage II and StageIII, 100 percent at Stage IV and Stage V in the Classification ofGlaucomatous Progression by the Auhlhorn-Greve modified method usingHumphrey perimeter. Some other glaucoma screening techniques have beenreported so far, but none of them shows a higher rate of detection thanthat achieved using this chart even at Stage I and Stage II.

[0052]FIG. 5 shows the fourth feature of the present invention,illustrating an eye test chart 1B on which enlarged circular targets 4 aenlarged from the pattern of the circular targets 4 arranged inside thegrid targets 3 are arranged vertically and horizontally in parallel. Theenlarged circular targets 4 a enable even a subject with too low visualacuity to identify the circular targets in the grid targets 3 or asubject with low sensitivity in the peripheral visual field to undergothe tests. The test procedure and method using this chart are the sameas those using the eye test chart 1 of FIG. 1 except for the enlargedcircular targets 4 a.

[0053]FIG. 6 shows the fifth feature of the present invention,illustrating an eye test chart 2C. Arranged on the eye test chart 2C aretargets extracted from the eye test chart in FIGS. 3 and 4 mainly forthe purpose of examining the eye's resolution. This chart aims to makeit easy to carry out the tests on cases of persons who have a reducedability to judge. A fixed target 43 of an easy-to-perceive shape, suchas a black cross, is arranged at the center of the chart. This chart isvertically and laterally symmetrical, so that not only the eye'sresolution but also visual differences between both eyes or hemianopiacan be examined.

[0054]FIG. 7 shows the sixth feature of the present invention,illustrating an eye test chart 2D on which the band-shaped targets 5 b,the Mariotte's blind-spot targets 6, and the blind-spot peripheraltargets 62 extracted from the eye test chart 2B in FIG. 4 are arranged.Like in FIG. 6, this chart aims to make it easy to carry out the testson cases of persons who have a reduced ability to judge. Also, like inFIG. 6, the black-cross fixed target 43 is placed at the center. The useof this chart enables a subject with too low visual acuity to identifythe checkered pattern of each of the square targets 4 b inside the gridtargets 3 b on the eye test chart 2B, or a subject who has a reducedability to judge, to visually identify the band-shaped targets 5 bcomposed of the enlarged square targets 4 c on the visually simplified,easy-to-view eye test chart 2D, while maintaining the correct distancebetween the eye test chart and the eye.

[0055] Although the above discloses the best modes for carrying out thepresent invention, the shape and placement of each target are notlimited to those shown in each figure, and the targets may have anycolor tone and shape, as long as they are clearly contrastive ordistinct, within the technical scope of the present invention.

[0056] The eye test scheme according to the present invention is suchthat multiple targets displayed for the purpose of examining differentsymptoms respectively in the manner mentioned above are arranged on onechart, thereby allowing eye tests of multiple items to be carried out atthe same time. This reduces test time and fatigue of the subject, andhence makes it easy to conduct the eye tests on subjects of all levelsof condition. Further, since multiple targets of different colors andshapes defined according to their positions are arranged on the chart,it is clear whether the subject can visually identify them or not.Furthermore, since the subject undergoes the examination after checkingthe placement and shape of each target, he or she can recognize anyabnormal region in his or her body and becomes aware of it. Furthermore,the examiner does not need expert knowledge and skills, so that detailedtests can easily be conducted not only at the Department ofOphthalmology or eye clinic but also at any other Department or placesother than medical institutions. In addition, the eye test charts can bemanufactured at low cost by printing them on synthetic resin plates,paper, etc., so that they can be placed in the waiting room at a medicalinstitution or pharmacy, or distributed to ordinary offices, houses,etc. It can be helpful for subjects to make a self-diagnosis and earlydetection of visual field defects and the like. Furthermore, since theeye test charts are small and light in weight, any person or examinermay hold a test chart up to adjust the position so that a subject canundergo the examination without changing his or her position. It enableseven a bedridden patient with a brain disease or the like to undergo theexamination.

INDUSTRIAL APPLICABILITY

[0057] As described above, the eye test chart scheme according to thepresent invention is such that multiple targets of various colors andshapes displayed for the purpose of examining different symptomsrespectively are arranged on one chart, thereby allowing eye tests ofmultiple items to be carried out at the same time. Since it reduces testtime and fatigue of the subject, it is useful for the eye tests.

[0058] Further, the targets have different colors and shapes, and thismakes it easy to judge whether the subject can visually identify thetargets or not. Thus, since the subject can become area of abnormalregions in his or her body, it is suitable for self-diagnosis of colordefective vision.

[0059] Further, the examiner does not need expert knowledge and skills,and it is useful for eye tests not only at the Department ofOphthalmology or eye clinic, but also at any other Department or placesother than medical institutions.

[0060] Furthermore, the eye test charts can be manufactured at low cost,so that they can be carried around or placed at various locations. Sincethis makes it easy for anyone to undergo the examination, the eye testcharts are suitable for early detection and progress observation of aneye or brain disease that causes a visual defect. In addition, since theeye test charts are light in weight and conveniently portable, they arealso suitable for medical checks or house visits by doctors on request.

1. An eye test chart characterized in that visual targets for multipletest purposes, composed of patterns of combinations of at least two ormore kinds of colors and predetermined shapes, are arranged atpredetermined positions on an image area corresponding to visual fieldregions to be examined, whereby color vision defects and their abnormalregions can be identified as a result of subject's visual identificationof the visual targets arranged at the predetermined positions.
 2. An eyetest chart according to claim 1, characterized in that said visualtargets are circular or square targets.
 3. An eye test chart accordingto claim 2, characterized in that said at least two or more kinds ofcolors are two kinds of colors different in hue from each other.
 4. Aneye test chart according to claim 3, characterized in that said at leasttwo or more kinds of colors are complementary colors.
 5. An eye testchart according to claim 1, 2, 3, or 4, characterized in that saidvisual targets are circular or square targets divided into four parts ina checkered pattern of a combination of two kinds of colors differentfrom the background color.
 6. An eye test chart according to claim 1, 2,3, or 4, characterized in that said visual targets are circular orsquare targets each composed of a vertical striped pattern of twodifferent kinds of colors.
 7. An eye test chart according to claim 6,characterized in that said vertical striped pattern is formed such thatone color shifts to the other in a sinusoidal fashion.
 8. An eye testchart according to claim 1, 2, 3, or 4, characterized in that a fixedtarget having a color or colors different from those of said circular orsquare targets, or a profile line bolder than those of the other targetsis arranged at the center, and grid targets composed of a grid ofsquares in which said circular or square targets are displayed arearranged in parallel around said fixed target in both the longitudinaland transverse directions.
 9. An eye test chart according to claim 8,characterized in that enlarged circular or square targets formed by justenlarging the pattern of said circular or square targets arranged insidesaid grid targets are arranged in parallel around said grid targets inboth the longitudinal and transverse directions.
 10. An eye test chartaccording to claim 1, 2, 3, or 4, characterized in that band-shapedtargets formed in the shape of a band with a checkered pattern ofmultiple squares, each composed of said striped pattern or checkeredpattern with the four divided parts, are arranged around its centralportion vertically and horizontally in parallel.
 11. An eye test chartaccording to claim 1, 2, 3, or 4, characterized in that a set ofblind-point targets for determining Mariotte's blind spot, composed of acombination of one or more black figures, is arranged at a predeterminedposition on said eye test chart in a bilaterally symmetrical pattern.12. An eye test chart according to claim 11, characterized in thatblind-spot peripheral targets, composed of multiple figures colored witha color different from the background color and easy to visuallyidentify on the background color, are arranged around said blind-spottargets in a bilaterally symmetrical pattern.
 13. An eye test chartaccording to claim 1, 2, 3, or 4, characterized in that large-sizedsquare targets, each of which is a black square larger than any othersingle circular or square target, and which contains two figures coloredwith the background color or a color of high lightness and spaced at apredetermined interval, are arranged on four corners of said eye testchart.
 14. An eye test chart according to claim 1, 2, 3, or 4,characterized in that at least two or more parallel square targets, eachof which is composed of a hollow figure shaped like a Chinese character“

” with the figure parts colored with a color different from thebackground color and easy to visually identify on the background colorand the hollow parts colored with the background color, are arranged atboth top and bottom sides, or at both right and left sides, in parallelin the transverse or longitudinal direction.
 15. An eye test chartaccording to claim 1, 2, 3, or 4, characterized in that at least two ormore parallel circular targets, each of which is composed of a hollowfigure shaped like a number “0” with the figure parts colored with acolor different from the background color and easy to visually identifyon the background color and the hollow parts colored with the backgroundcolor, are arranged at both top and bottom sides, or at both right andleft sides, in parallel in the transverse or longitudinal direction. 16.An eye test chart according to claim 1, 2, 3, or 4, characterized inthat said targets are arranged in a bilaterally symmetrical pattern.